抄録
In the extensive literature on passerine song, there has been much debate on whether the main function is territorial or sexual. Sexual selection theory provides a unifying conceptual framework which recognises the importance of both these functions which are not mutually exclusive. In Acrocephalus warblers the two different kinds of sexual selection pressure may have led to the evolution of two main types of song. Long, complex songs have developed primarily for sexual attraction and short, simple songs mainly for territorial defence. In each case, sexual selection is the main evolutionary force, and female choice acts either directly or indirectly to produce the optimal song structure for each species with its particular ecology and mating system.The ultimate goal of all singing behaviour is to directly or indirectly maximise the reproductive success of the individual.
